The present invention relates to a fixing apparatus for fixing toner images on recording media and image forming apparatus comprising the fixing apparatus.
Image forming apparatuses adopting electrophotography comprise a fixing apparatus which fixes toner images formed on recording media. Such fixing apparatuses include those adopting a heating and pressing method. Fixing apparatuses adopting this method each comprise a heating roller and a pressure roller, carry recording media between the both rollers by rotating the rollers, and heat and press toner images to fix them on the recording media.
In the fixing apparatus, sometimes the situation in which recording media are not conveyed but stopped and jammed (paper jam) occurs, which hinders a fixing operation. For example, there are cases where a recording medium is curved by heat of the heating roller, collides with parts provided in the vicinity of the heating roller, and stops.
Therefore, image forming apparatuses are each provided with an opening portion and a cover for opening/closing the opening portion at a case surrounding the rollers, such that jammed recording media can be removed. Normally, the cover closes the opening portion to prevent the operator from touching the rollers by hand. When paper jam occurs, the operator can open the cover and insert the hands into the case through the opening portion to take out the jammed recording media.
When the cover is unstable to the case at the position where the opening portion is closed, a problem occurs that the cover vibrates and causes noise. It is thus necessary to secure the cover to the case.
Therefore, in the conventional art, the cover is secured to the case by using screws in the state where the cover is closed. Specifically, tapped holes are formed at the case, and plain holes are formed at the cover. Screws are screwed into the tapped holes of the case from the outside of the cover through the plain holes of the cover.
In the structure, when the cover is to be secured to the case, by using tools, an operation is performed to insert screws into the tapped holes of the case through the plain holes of the cover, and engage them into the tapped holes by turning the screws in the direction of tightening them. When the cover is released from fixation to the case, an operation is performed to extract the screws from the tapped holes of the case and the plain holes of the cover by turning the screws in the direction of loosening them by using tools.
As described above, when the cover is fixed to the case or released from the fixation, it is necessary to turn the screws by using tools. Specifically, when the cover is fixed to the case and the cover is released from the fixation, required are an operation to carry a tool to the part in which the cover is provided, an operation to engage the tool with each screw to turn them, and an operation to carry the tool from the part in which the cover is provided.
Therefore, when recording media are jammed in the fixing apparatus, much labor and time are required for the process to open the cover and extract the jammed recording media from the inside of the case.
The present invention is to provide a fixing apparatus, which has an improved structure of fixing an openable/closable cover provided at a case surrounding a fixing device, and enables an easy and prompt processing in the case where recording media have been jammed.
The present invention is to provide an image forming apparatus comprising the fixing apparatus.
A fixing apparatus according to an embodiment of the present invention comprises: a fixing device which fixes an unfixed toner image formed on the recording medium while conveying a recording medium; a case which surrounds the fixing device and has an opening portion;
a cover provided on the case so as to open and close the opening portion of the case; a cover-fixing shaft which is provided on the cover so as to be detachable to the case, a part of the cover-fixing shaft projecting outside the cover; a knob which is provided on the cover-fixing shaft to be movable along its axial direction and projects to the outside of the cover-fixing shaft by movement; an elastic member which is provided on the cover-fixing shaft and applies force to the knob in a direction away from the cover; and a stopper which prevents movement of the knob against force of the elastic member.
An image forming apparatus according to an embodiment of the present invention comprises: an apparatus main body having an open portion; a door which is provided on the apparatus main body to open and close the open portion; a photosensitive member which is provided inside the apparatus main body to form a toner image; a transfer member which is provided inside the apparatus main body to transfer the toner image of the photosensitive member onto a recording medium; and a fixing apparatus which is provided inside the apparatus main body, facing the open portion, and fixes the toner image transferred onto the recording medium, the fixing apparatus further comprising: a fixing device which fixes a toner image formed on the recording medium while conveying a recording medium; a case which surrounds the fixing device and has an opening portion; a cover provided on the case so as to open and close the opening portion of the case; a cover-fixing shaft which is provided on the cover so as to be detachable to the case, a part of the cover-fixing shaft projecting outside the cover; a knob which is provided on the cover-fixing shaft to be movable along its axial direction and projects to the outside of the cover-fixing shaft by movement of the shaft; an elastic member which is provided on the cover-fixing shaft and applies force to the knob in a direction away from the cover; and a stopper which prevents movement of the knob against force of the elastic member.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.